SuperMonsoon Hits the Southwest U.S. and the Northwest Will get a Piece of It.

 There’s a good identify for it:   a SuperMonsoon.

In my earlier blogs, I talked in regards to the nature of the Southwest (or North American) Monsoon, and the way water vapor from the Gulf of Mexico swings round a high-pressure space into the Desert Southwest from June to August.

Consequently, the southwest U.S. is often MUCH wetter than the Pacific Northwest throughout mid-summer.

The Southwest Monsoon has been significantly energetic this summer time with a lot of thunderstorms and an uncommon westward and northward penetration of moisture.

Check out the % of regular rainfall in the course of the previous month.   

Wow.  Some areas (Nevada and southwest California) have been hit by over 800% of regular rainfall.  Of us wanted an umbrella in Las Vegas!

The previous week has been significantly moist, with giant quantities of monsoon moisture pushing into japanese Oregon! (see under).  A lot of that precipitation was related to lightning, inflicting a number of fires.

This summer time’s monsoon has been related to uncommon quantities of water vapor shifting northward out of the tropics.  

To reveal this to you, under is a plot of water vapor anomaly (distinction from regular) for June 1 to August thirteenth.  Greens to crimson are above regular.  Wow…a lot of oranges and reds….properly above regular water vapor quantities heading northwestward out of Mexico into the Desert Southwest!   A few of it even reaches the Pacific Northwest.

With all of the moisture, bringing precipitation and thunderstorms, the Las Vegas  Nationwide Climate Service have been busy placing out flash flood warnings (see one from yesterday under)

Wanting on the complete rainfall map since June 1, solely displaying values above 1.5 inches, a lot of areas within the southwest have gotten over 4 inches, with a number of areas getting 5-17 inches.

Attention-grabbing, final 12 months was additionally an enormous Southwest Monsoon 12 months…in truth, much more spectacular than this 12 months.  

Is there a development in  Southwest Monsoon rainfall?  To realize some perception into this query, under is a plot of July Arizona rainfall for over a century.  

This 12 months the July rainfall throughout Arizona is clearly above regular (and the heaviest precipitation was throughout August), however final 12 months had distinctive July rain.   Some actually heavy rain about 100 years in the past, and July 2020 was very dry.   However all and all, quite a lot of precipitation variability however with little development.

Some local weather mannequin research counsel that the Southwest Monsoon will get drier and others mission little general change (drier first half, wetter second half of the summer time).  However considerating that thunderstorms/convection produces most monsoon rainfall and that local weather fashions do not deal with them properly, I believe the jury remains to be out on the subject.

One remaining factor.  Final 12 months’s bountiful Southwest Monsoon resulted in heavy grass progress that contributed to the horrible New Mexico fires earlier this 12 months.    The Forest Service, BLM,  and different wildfire businesses will should be ready for an energetic wildfire season subsequent 12 months.